when speaking to legate rikke the reporting for duty will not appear and this can happen with anytime in the civil war quest line. now whats my proof of this bug, well it's a vary very common bug and if cant reproduce this bug for some reason just type legate rikke bug or reporting for duty bug in to google and you will find many reports of this bug.

now people have ways around this bug like going to older save or cooking a pot of stew but a lot of these workarounds have side effects like:

taking 10 in game or real time minutes for the quest start
When asked to join the men attacking at a fort, there may be no men to join
every one at the fort that you are supposed be attacking are dead or did not spawn making the quest unwinnable


I hope its fixed in 1.9